In general, a refrigeration-type refrigerated transport service and a freezing-type refrigerated transport service are used as refrigerated transport services. With each refrigerated transport service, a package is distributed in an environment where a predetermined temperature zone is maintained. The environment means a cold-insulation box, a refrigerator car, a refrigerator truck, a cold-insulation container, or the like that includes one or more sensors for controlling the environment. A refrigerator or a freezer fixed to the cold-insulation box or the like adjusts its output based on output (data) from the sensor so that the predetermined temperature zone can be maintained.
A sensor is also used in an air conditioner that creates a car environment of a motor vehicle. The air conditioner of the motor vehicle controls a plurality of items such as capability of air-conditioning or heating, a vent to be used, and wind strength based on output (data) from the sensor so that the temperature of the motor vehicle can be set to temperature determined by a user of the motor vehicle. Moreover, in an expensive motor vehicle, controlling individual seats at different temperatures for individual passengers is becoming more common.
One of the methods that have been proposed to achieve higher performance, such as a reduction in power consumption of a semiconductor device and miniaturization, is the use of an oxide semiconductor for a semiconductor layer (hereinafter also referred to as an active layer, a channel layer, or a channel formation region in some cases) of a transistor in a semiconductor device. An example of the transistor includes an oxide of indium, gallium, and zinc (hereinafter also referred to as an In—Ga—Zn oxide in some cases) for a channel layer (see Patent Document 1).